A vehicle power transmission device disposed between an engine and drive wheels is known. For example, this corresponds to those described in Patent Documents 1 to 4. Patent documents 1 and 2 describe a vehicle power transmission device including a first planetary gear device distributing power from the engine to a first electric motor and a cylindrical output member having an output gear disposed on a portion in an axial center line direction on the outer circumferential side, and a second planetary gear device having a second sun gear coupled to a second electric motor, a second carrier fixed to a case, and a second ring gear coupled to an inner circumference of the cylindrical output member to reduce and transmit output rotation of the second electric motor to the cylindrical output member.